Almost 1,000 schools are waiting for renovations or replacement buildings, according to the latest official figures.
A total of 341 schools are on existing building programmes which remain to be delivered.
In addition, there are about 575 school applications for major refurbishments on hand which the department has not been able to prioritise to date.
Fianna Fáil's education spokesman, Thomas Byrne TD, expressed shock at the scale of the numbers and how long many schools have been force to wait for replacement buildings.
Department of Education officials acknowledged at an Oireachtas education committee meeting earlier this week that there has been an historic under-investment in the sector.
However, Hubert Loftus, the department's assistant secretary general, told the committee that investment in recent years had ramped up and 365 "large-scale projects" had been completed since 2010, providing about 130,000 school places.
The National Development Plan, he said, would involve significant additional investment over the coming decade.
Mr Byrne also questioned whether school renovations and other projects were being put on hold to provide for new schools, such as last week’s announced plans for the establishment of 42 new schools over the next four years.
A spokeswoman for the department said on Wednesday that any new schools which were gradually starting up (where, for instance, the intake for a new primary school starts with junior infants only) would typically involve the use of interim accommodation.
“As the 42 new schools will likely start in interim accommodation to begin with, the capital spend for their permanent buildings will be in the medium term,” she said.
“Therefore, it is not correct to say that these 42 new schools are at the expense of those schools who have written to the department asking for funding to carry out refurbishments.”
Prefab use
Other figures indicate there has been an increase of more than 25 per cent in the number of prefabs being used in schools between 2016 and 2017.
Mr Byrne said this showed the school-building programme was not keeping up with demand.
However, a department spokeswoman said prefabs were a short-term solution to urgent accommodation needs, such as the appointment of extra teachers.
“We have recruited an additional 5,000 extra teachers over the past two years,” she said.
She added that the number of prefabs had reduced significantly over the past decade, falling about 2,000 in 2008 to 1,325 at the end of last year.
“The Government has committed to replacing all purchased temporary accommodation with permanent accommodation, where the need is established, by 2021,” she said.
A new prefab-replacement scheme will begin next year and the Government has committed €180 million to the scheme.
